Special industrial applications targeted to remote locations or highly-distributed system architectures (“Smart Dust” sensors, for example) call for the operation of electronic systems that are to be powered by energy harvested from the environment, without the need for a local battery or wired energy source. Since the amount of energy that can be derived from vibrations (or other mechanical motion) of the apparatus, light impinging on it, or electromagnetic field in its vicinity is extremely small, these systems are required to be designed for extreme energy efficiency—in both their analog and digital components.
One such electronic device that is most commonly needed in sensors is a simple event counter. By way of example, water or electrical utility meters rely on physical phenomena capable of translating the flow of the physical entity to be metered into a quantized electrical pulse, which can then be counted to quantify the consumption. Vibration sensors, such as strain gauges, can exploit piezoelectric properties of materials to produce pulses that, once counted, provide information as to the frequency and pattern of the motion under observation. The same principle can be applied to sensors, such as rotational encoders and distributed sensing for haptics solutions.